Can you use IDS If you just buy the IDS and softcap data

So here is my question.

Telkom 20GB softcap costs 99 Bucks a month and their 20 GB IDS costs another 99 Bucks per month
SO my question is can i pay for just both of these and use the IDS or do i have to link the softcap to a DSL line which would then set me back another 169 Bucks /m
Because this would be a cheap alternative to mobile data if you dont need to pay the ADSL line rental


Also is it possible to port a number to an IDS simcard?